Fluid pressure modulating valves

ABSTRACT

An electromagnetically controlled fluid pressure modulating valve comprises a cylindrical body within which a valve piston is freely movable. The valve piston controls the opening and closing of inlet and outlet passageways by means of a conical valve seat ground on one end of the piston and a corresponding seat on the end of the cylinder. The piston has a passageway permitting the flow of fluid into the blind end of the cylinder to substantially equalize the fluid pressure on both sides of the piston. The valve piston forms the movable core of an electromagnet the current flowing through which determines the position of the piston and therefore the amount of fluid flow through valve.

States Patent ichellone et a1.

[ 1 Aug. 15, 1972 [541 FLUID PRESSURE MODULATING VALVES [22] Filed: Oct.21, 1970 [21] Appl. No.: 82,666

[30] Foreign Application Priority Data.

Nov. 27, 1969 Italy ..54l89 N69 [52] US. Cl. ..251/129, 251/141, 251/282[51] Int. Cl. ..Fl6k 3l/06, F16k 39/04 [58] Field ofSearch ..251/141,129,282

[56] References Cited UNITED STATES PATENTS 3,446,473 5/1969 Barker ..251/ 129 X 3,100,103 7/1963 Bullard ..251/141 X 3,531,080 9/1970 Dillon..251/129 2,841,216 7/1958 McKinnon ..251/141 X FOREIGN PATENTS ORAPPLICATIONS 33,074 11/1964 Germany ..251/141 Primary ExaminerArnoldRosenthal Attorney- Sughrue, Rothwell, Mion, Zinn & Macpeak [5 7]ABSTRACT An electromagnetically controlled fluid pressure modulatingvalve comprises a cylindrical body within which a valve piston is freelymovable. The valve piston controls the opening and closing of inlet andoutlet passageways by means of a conical valve seat ground on one end ofthe piston and a corresponding seat on the end of the cylinder. Thepiston has a passageway permitting the flow of fluid into the blind endof the cylinder to substantially equalize the fluid pressure on bothsides of the piston. The valve piston forms the movable core of anelectromagnet the current flowing through which determines the positionof the piston and therefore the amount of fluid flow through valve.

1 Claim, 3 Drawing Figures PATENTED 3,684,238

SHEET 1 0F 2 INVENTORS Q/A/Y C4240 Mame-0H5 MAR/0 PALAZZETT/ BY J M)ATTORNEYS PATENTEDAUS 1 1 12 3,684,238

SHEET 2 OF 2 FLUID P MODULATING VALVES The present invention relates toan electromagnetically controlled valve for modulating fluid pressure.

Electromagnetically controlled valves for varying the pressure of afluid supplied to a pressure responsive device are already known. Ingeneral, however, they are of a rather complicated construction andinclude a large number of parts which are mostly machined to size withinvery rigorous tolerances. As a consequence of this their application islimited to. apparatus in which the cost is of secondary importance.

In order to produce on electromagnetic pressure modulating valveeconomically, it is necessary to have a reduced number of parts, andmoreover, they must be parts which do not require very rigorousmanufacturing tolerances or have a complicated structure which requiresassembling. Preferably they should be suitable for economicalmanufacture using modern mass production methods. Another disadvantageof valves of the known type is that they require relatively highelectrical power for their operation.

According to the present invention there is provided anelectromagnetically controlled valve for modulating fluid pressure,comprising a substantially cylindrical body having fluid inlet andoutlet passageways fluid flow through which is controlled by a valvepiston which is movably mounted within the said cylindrical body, thevalve piston forming the core of an electromagnet the winding of whichsurrounds the cylindrical body, and the position of the valve pistonwithin the cylindrical body being controlled by the current in thewinding.

One embodiment of the present invention will now be more particularlydescribed, by way of example, with reference to the accompanyingdrawings, in which,

FIG. 1 is a front view of a valve constructed in accordance with thepresent invention;

FIG. 2 is a sectional view of the embodiment of FIG. 1 taken along theline 11 11; and

FIG. 3 is a schematic representation of one application of the valveshown in FIGS. 1 and 2 in a fluid circult.

In the description which follows it is assumed that the fluid is oil.

With reference to FIGS. 1 and 2, there is shown a valve body 10, havinga cylindrical bore 11 which has an open end A and a closed end 10B. Avalve piston 14 is freely movable within the bore 11 and has one of itsend faces 13 adapted to mate against a conical seat 16 with afrusto-conical face 17. The valve seat 16 is formed in a cylinder headattachment l2, fixed to the body of the cylinder 10 by screws 18 screwedin holes 20. The cylinder head 12 forms a passageway for the oil and anexternal connector for the valve to connect it into a fluid circuit. Anannular chamber 24 communicates with the bore 11 of the cylinder 10 anda plurality of radial passageways 22, only one of which is representedin FIG. 2, provide the outlet for the oil which can pass from the inletpassageway 12A to the outlet passageways 22 only when the valve pistonis clear of the conical seat 16. If the valve is mounted in a tank sothat the oil discharges directly into the tank the discharge can beeffected with no output connections.

The closed end 108 of the cylindrical body 10 has a threaded aperture 33in which a threaded screw plug 34 is fitted. The position of the plug 34can be adjusted to regulate the position of a support disc 36. Betweenthis disc 36 and the valve piston 14, a chamber 28 is formed, in which acompression spring 38 is mounted, which biasses the piston 14, to pressagainst the conical seat 16 to a normally closed position.

An elongate axial passageway 26 is formed in the valve piston; thisallows the oil contained in the input passageway 12A to reach chamber 28so that there is substantially the same fluid pressure on both faces l3.15 of the piston 14. The small difference being due to the loss ofpressure in the annular zone 17 which forms the valve.

The valve piston 14, which is constructed of ferromagnetic material,forms the core of an electromagnetic coil 32 which surrounds the body 10of the valve and which, when energized applies to the valve piston aforce substantially proportional to the intensity of current which isflowing in the coil. The coil itself is enclosed in a ferromagneticcover formed by two parts 48 and 50, and is kept in position on the body10 by a sleeve 37 which locks it against the support of a flange 52 ofthe body 10. The body 10 is not made of a ferromagnetic material. Thesleeve 37 is in its turn held in place by a nut 35 screwed on thethreaded external sur-v face of the end 108 of the body 10.

The construction of the valve is such as to make the piston 14 work inthe zone of maximum force exerted by the electromagnet 32. The controlforce of the electromagnet must thus, in practice, only overcome thesmall returning force of the spring 38 neglecting the small force due tothe pressure not acting on the annular surface 17. A small electricalpower is therefore sufficient to control the position of the valvepiston 14, moving it away from the conical seat 16, and varying the flowof the oil.

By adjusting the position of the disc 36 with the screw 34 it ispossible to regulate the force of the spring and thereby to vary thesensitivity of the valve to the electric control signal applied to thecoil 32.

The valve does not require any special manufacturing for the fit betweenthe piston 14 and the valve cylinder 1 1, because even if the fit is notfluid-tight this does not cause inconvenience. On the other hand a smallamount of play is useful to allow a good lubrication and an easy slidingof the piston 14 within the bore 11.

The only two parts in which fluid-tight joints are required, are theconnections of the cylinder head 12 and the screw 34 to the respectiveparts of the body 10. A fluid-tight engagement is in fact ensured hereby two O-rings 40 and 42.

According to an embodiment of this invention which is not illustratedthe possibility is envisaged of varying the section of the passageway 26along the valve piston 14 in order to regulate the operation of thevalve.

In FIG. 3 there is shown an application of the valve according to theinvention in a fluid circuit. A valve E is placed in parallel connectionto a pump P which supplies fluid under pressure along a tube C to adevice U which is responsive to the pressure in the fluid. When thevalve is open the oil circulates without increasing in pressure. Byreducing the opening the pressure in the pipe C can be increased to thepoint of obtaining the whole pressure supplied by the pump p.

Although only a preferred embodiment of the invention has been describedit is clear that there are possible modifications and variations to whathas been illustrated without departing from the scope of this inventron.

Thus, for example, the spring 28 could be mounted on the other side ofthe valve piston 14 naturally with due adaptation of the connection 12.In such case, the spring would act on the piston so as to keep itnormally away from the seat 16 and the force on the piston by themagnetic circuit must be modified so as to move the valve piston to aclosing position when the coil is energized.

Furthermore the conical seat 16 could be flat or spherical. Instead ofonly one longitudinal passageway 26, the valve piston could have manymore for the aims above specified.

What is claimed is:

l. A solenoid operated fluid pressure modulating valve, a nonmagneticvalve body defining a cavity hav ing inlet passage means and outletpassage means at one end thereof, said inlet passage means defining avalve seat within said cavity, solenoid means surrounding said body, asubstantially cylindrical piston of a ferro magnetic material movablydisposed in said cavity in axial alignment with said inlet passage meanswith one end face thereof adapted to engage said valve seat to variablyrestrict the flow of fluid from said inlet passage means to said outletpassage means under the action of a magnetic force exerted upon saidpiston by said solenoid means when energized, said cavity in said valvebody being closed at its end remote from said inlet and outlet means todefine a chamber adjacent the other end face of said piston, said pistonhaving a longitudinal bore for permanent connection of the inlet passagemeans to said chamber whereby substantially equal pressures will beexerted by the fluid on both end faces of said piston, and adjustablespring means disposed in said chamber for biasing said piston forengagement with said valve seat.

1. A solenoid operated fluid pressure modulating valve, a nonmagneticvalve body defining a cavity having inlet passage means and outletpassage means at one end thereof, said inlet passage means defining avalve seat within said cavity, solenoid means surrounding said body, asubstantially cylindrical piston of a ferro magnetic material movablydisposed in said cavity in axial alignment with said inlet passage meanswith one end face thereof adapted to engage said valve seat to variablyrestrict the flow of fluid from said inlet passage means to said outletpassage means under the action of a magnetic force exerted upon saidpiston by said solenoid means when energized, said cavity in said valvebody being closed at its end remote from said inlet and outlet means todefine a chamber adjacent the other end face of said piston, said pistonhaving a longitudinal bore for permanent connection of the inlet passagemeans to said chamber whereby substantially equal pressures will beexerted by the fluid on both end faces of said piston, and adjustablespring means disposed in said chamber for biasing said piston forengagement with said valve seat.